Frontear is a classic Spanglish verb popular in reggaeton, adapted from the English phrase "to front". It means to show off, act tough, or boast about your status and lifestyle, often in a defiant way.
In the song, Bad Bunny feels responsible for his ex's new wild attitude. He sings, "Yo fui el que te enseñé... a frontear como es" (I was the one who taught you... how to front properly), revealing that he taught her the very behavior he now dislikes seeing in her.
Puerto Rican superstar Bad Bunny serves up a hilarious mix of hurt pride and sheer disbelief in "KETU TeCRÉ". He watches an ex completely transform after their breakup, asking "¿Cómo fue que terminamos siendo enemigos?" [How did we end up as enemies?]. In his eyes, he created a monster: "Siento que yo te cambié" [I feel like I changed you]. Back when they dated, she was low-key, but now she is out every single weekend partying ("perrear" / dancing reggaeton), blasting classic throwbacks from Plan B and Jowell & Randy, and posting Cardi B style twerking videos on her social media. He complains that he taught her how to flex—"Yo fui el que te enseñé / A frontear como es / A tirar chavos en el club" [I was the one who taught you how to front properly, how to throw cash in the club]—and now she thinks she is too cool for him.
The lyrics paint a wild, funny portrait of her new lifestyle: she drinks matcha by day and tequila by night, rocks fresh nails and eyelashes, and scouts out guys wearing luxury watches like an AP (Audemars Piguet) or a Rolex. Bad Bunny calls her out for acting "embichá" (Puerto Rican slang for act stuck-up or full of herself) and "malcriada" [spoiled/ill-mannered], asking "¿Qué carajo tú te crees?" [Who the hell do you think you are?]. By the end, between telling her to ignore his calls ("voy a pichar" / I'm going to ignore you) and letting her live like the Dominican rapper Tokischa ("Sigue ruli, Tokischa"), his wounded ego slips through: it drives him crazy to show real feelings to someone who ended up not deserving them.